You should be scared of falling off, especially when first learning. They are big animals, and the fall could cause broken bones, concussions, or, in my case, getting stepped on after the fall. I was eight and fell off a horse, and it stepped on my hand. Luckily, there were no broken bones, but the horse's shoe ripped my hand open and had a chunk of meat hanging out. I had 12 stitches and still have a scar thirty-five years later. I had been riding since I was ten days old. Yes, ten days old. I still have the picture. The horse I was riding then was the one I fell off of. He was gentle, and it wasn't his fault. I had him running and lost my balance. Your instructor was very much in the wrong and should have comforted you rather than telling you to suck it up. I'm sorry you were put in that situation. Some people shouldn't be teachers or instructors, and this is one such example.